Changing the hierarchy of an existing multisite

[anorthite]

I have two Drupal sites sharing the same CiviCRM database and a third to add. The original site, which gathered the contacts, is becoming less important and will eventually be dropped. The newest site is going to become the parent of the second site. Is this a simple matter of changing the group and org IDs in civicrm.settings.php to reflect the new relationships? Are the group and org IDs even necessary to use with a multisite installation if maintaining a hierarchy isn't required by the user?

[Eileen]

If you are not retaining the hierarchy the groups don't need to be nested - the main thing defining the groups will do (if you don't use the permissioning extension) is cause the contacts to be added to the site group they were created on.